Capacitive sensing apparatus

ABSTRACT

A capacitive sensor apparatus comprises a first sensing element and a second sensing element. The first sensing element has a length oriented along a first axis of a contactable capacitive sensing reference surface; has a substantially constant width along its length; and is configured to have varying capacitive coupling, along the first axis, to an object proximate to the contactable capacitive sensing reference surface. The second sensing element has a length oriented along the first axis; has substantially constant width along its length; and is configured to have varying capacitive coupling, along the first axis, to the object proximate to the contactable capacitive sensing reference surface. The first sensing and second sensing elements are conductive and are configured to provide information corresponding to a spatial location of the object relative to the first axis.

CROSS REFERENCE TO RELATED APPLICATION (DIVISIONAL)

This application claims priority and is a divisional to the patentapplication, Ser. No. 10/922,574, entitled “Capacitive Sensing ApparatusHaving Varying Depth Sensing Elements,” by Bob Lee Mackey, with filingdate Aug. 19, 2004 now U.S. Pat. No. 7,737,953, and assigned to theassignee of the present invention, the disclosure of which is herebyincorporated herein by reference.

BACKGROUND

Conventional computing devices provide several ways for enabling a userto input a choice or a selection. For example, a user can use one ormore keys of an alphanumeric keyboard communicatively connected to thecomputing device in order to indicate a choice or selection.Additionally, a user can use a cursor control device communicativelyconnected to the computing device to indicate a choice. Also, a user canuse a microphone communicatively connected to the computing device toaudibly indicate a particular selection. Moreover, touch-sensingtechnology can be used to provide an input selection to a computingdevice or other electronic device.

Within the broad category of touch sensing technology there existcapacitive sensing touch screens and touch pads. Among commerciallyavailable capacitive sensing touch pads, there are varying patterns ofsensing elements. Typical of these sensing elements are traces formed intwo layers, one layer running in an x-direction and the other layerrunning in a y-direction. The location of a finger or other object inrelation to the capacitive sensing device is determined from the x-ytrace signals. However, there are disadvantages associated with thistwo-layer formation of x and y patterns of traces. For instance, one ofthe disadvantages is that the x and y patterns typically require thatthe x-traces and the y-traces intersect without touching. Thus, themanufacturing process becomes more complicated in order to maintainseparation of traces while striving to maintain a small form factor. Afurther complication in the manufacture of a touch pad having two layersof traces is that of alignment of the two sets of traces.

Another commercially available sensing technology exists in which asingle layer of traces is used in which each trace is connected to anarea on the touch pad and then the areas are enumerated. However, thereare also disadvantages associated with this commercially availablesensing technology. For example, one of the disadvantages is that thereis no redundancy in the sensing information, which leads to asubstantial vulnerability to noise.

One other conventional sensing technology involves the use of sensingelectrodes formed in triangular shapes wherein the direction of eachtriangle point alternates. However, there are disadvantages associatedwith this technique. For instance, one of the disadvantages is that as afinger (or object) moves towards the wide end of a first triangularshaped electrode and the narrow point of a second triangular shapedelectrode, the narrow point electrode does not provide a quality signalbecause of its inherent signal to noise ratio. As such, this can bereferred to as sensing geometry that induces signal to noise ratioconcerns.

The present invention may address one or more of the above issues.

SUMMARY

One embodiment in accordance with the invention can include a capacitivesensor apparatus that includes a first sensing element havingsubstantially constant width along its length and configured to havevarying capacitive coupling to an object proximate to a capacitivesensing reference surface, along a first axis of the capacitive sensingreference surface. The length of the first sensing element can beoriented along the first axis. The capacitive sensor apparatus caninclude a second sensing element having substantially constant widthalong its length and configured to have varying capacitive coupling tothe object proximate to the capacitive sensing reference surface alongthe first axis. The length of the second sensing element can be orientedalong the first axis. The first and second sensing elements areconductive, and are configured to provide information corresponding to aspatial location of the object relative to the first axis of thecapacitive sensing reference surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary capacitive touch screen device that can beimplemented to include one or more embodiments of the invention.

FIG. 2 is a side sectional view of an exemplary capacitive sensorpattern in accordance with embodiments of the invention.

FIG. 3 is a side sectional view of an exemplary capacitive sensorpattern in accordance with embodiments of the invention.

FIGS. 3A, 3B, 3C, 3D, and 3E are general cross sectional views inaccordance with embodiments of the invention of the capacitive sensorpattern of FIG. 3.

FIG. 4 is a side sectional view of an exemplary capacitive sensorpattern in accordance with embodiments of the invention.

FIGS. 4A, 4B, 4C, 4D, 4E, 4F, and 4G are general cross sectional viewsin accordance with embodiments of the invention of the capacitive sensorpattern of FIG. 4.

FIG. 5 is a side sectional view of an exemplary capacitive sensorpattern in accordance with embodiments of the invention.

FIGS. 5A, 5B, 5C, 5D, and 5E are general cross sectional views inaccordance with embodiments of the invention of the capacitive sensorpattern of FIG. 5.

FIG. 6 illustrates an exemplary signal strength chart along with itsconversion into polar coordinates in accordance with embodiments of theinvention.

FIG. 7A is a cross sectional view of an exemplary capacitive sensorpattern in accordance with embodiments of the invention.

FIGS. 7B, 7C, 7D, and 7E are lengthwise side sectional views inaccordance with embodiments of the invention of the capacitive sensorpattern of FIG. 7A.

FIG. 8 is a plan view of an exemplary capacitive sensor patternincluding electrical connections in accordance with embodiments of theinvention.

FIG. 9 is a plan view of an exemplary sensor pattern in accordance withembodiments of the invention.

FIGS. 10A and 10B are side sectional views of an exemplary capacitivesensor pattern in accordance with embodiments of the invention.

FIG. 11 is a plan view of an exemplary loop capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 12 is a plan view of an exemplary loop capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 13 is a plan view of an exemplary loop capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 14 is a plan view of an exemplary loop capacitive sensor pattern inaccordance with embodiments of the invention.

FIG. 15 is a plan view of an exemplary “fishbone” capacitive sensorpattern in accordance with embodiments of the invention.

FIG. 16 is a flowchart of a method in accordance with embodiments of theinvention.

The drawings referred to in this description should not be understood asbeing drawn to scale unless specifically noted.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the invention,examples of which are illustrated in the accompanying drawings. Whilethe invention will be described in conjunction with embodiments, it willbe understood that they are not intended to limit the invention to theseembodiments. On the contrary, the invention is intended to coveralternatives, modifications and equivalents, which may be includedwithin the scope of the invention as defined by the appended claims.Furthermore, in the following detailed description of embodiments inaccordance with the invention, numerous specific details are set forthin order to provide a thorough understanding of the invention. However,it will be evident to one of ordinary skill in the art that theinvention may be practiced without these specific details. In otherinstances, well known methods, procedures, components, and circuits havenot been described in detail as not to unnecessarily obscure aspects ofthe invention.

FIG. 1 is a plan view of an exemplary single layer capacitive sensorapparatus 100 that can be implemented to include one or more embodimentsof the present invention. The capacitive sensor apparatus 100 can beutilized to communicate user input (e.g., using a user's finger or aprobe) to a computing device or other electronic device. For example,capacitive sensor device 100 can be implemented as a capacitive touchpad device that can be formed on a computing device or other electronicdevice to enable a user interfacing with the device. It is noted thatone or more embodiments in accordance with the present invention can beincorporated with a capacitive touch pad device similar to capacitivesensor apparatus 100.

The capacitive sensor apparatus 100 when implemented as a touch pad caninclude a substrate 102 having a first set of conductive coupling traces104 and a second set of conductive coupling traces 106 patterned (orformed) thereon. Substrate 102 of capacitive sensor apparatus 100 can beimplemented with, but is not limited to, one or more opaque materialsthat are utilized as a substrate for a capacitive touch pad device.Conductive coupling traces 104 and/or 106 can be utilized for couplingany sensing elements (not shown) that would form a sensing region 108with sensing circuitry 110 thereby enabling the operation of capacitivesensor apparatus 100. Conductive coupling traces 104 and 106 may eachinclude one or more conductive coupling elements or traces. It is notedthat embodiments of sensing element patterns in accordance with theinvention are described herein which can be implemented to form sensingregion 108.

Within FIG. 1, the capacitive sensor apparatus 100 can also beimplemented as a capacitive touch screen device. For example, substrate102 of capacitive sensor apparatus 100 can be implemented with, but isnot limited to, one or more substantially transparent materials that areutilized as a substrate for a capacitive touch screen device.

FIG. 2 is a side sectional view of an exemplary capacitive sensorpattern 200 in accordance with embodiments of the invention.Specifically, sensor pattern 200 includes sensing elements 206 and 208which can be utilized as part of a capacitive sensor apparatus (e.g.,100), such as but not limited to, a touchpad. When electrically coupledto sensing circuitry (e.g., 110), sensor pattern 200 providespositioning information which can be derived from which sensing elementdetects an object (e.g., a user's finger, a probe, and the like), andthe proportional strength of the signals on sensing elements 206 and208.

Each of sensing elements 206 and 208 can have a substantially constantwidth along its length and can be configured to have varying capacitivecoupling to an object proximate to a capacitive sensing referencesurface 202 along a first axis (e.g., X axis) of the reference surface202. Note that the length of each of sensing elements 206 and 208 can beoriented along the first axis. The sensing elements 206 and 208 areconductive, and are configured to provide information corresponding to aspatial location of the object relative to the first axis of thecapacitive sensing reference surface 202. Note that sensing elements 206and 208 can separately provide the information corresponding to aspatial location of the object.

Within FIG. 2, each of sensing elements 206 and 208 can include a stripof conductive material that is substantially straight and decreases indistance relative to the capacitance sensing surface 202 along the firstaxis. Therefore, when sensing element 206 is coupled with sensingcircuitry (e.g., 110), it can have varying capacitive coupling to anobject proximate to the sensing reference surface 202 as the objectmoves along the length of sensing element 206. As such, a differentsignal strength is provided by sensing element 206 that is associatedwith each position or location along its length. It is appreciated thatwhen sensing element 208 is coupled with sensing circuitry (e.g., 110),it can operate in a manner similar to sensing element 206, as describedabove.

Specifically, sensing elements 206 and 208 of sensor pattern 200 can beembedded within a substrate material (e.g., 102). The distance thatsensing element 206 is separated from the capacitive sensing referencesurface 202 varies along the length of sensing element 206. For example,distance (or depth) 212 is the closest that sensing element 206 is tothe capacitive sensing reference surface 202 while distance (or depth)218 is the furthest that the upper surface of sensing element 206 isfrom reference surface 202. The upper surface of sensing element 206increasingly slopes away from capacitive sensing reference surface 202.Moreover, the distance that sensing element 208 is separated from thecapacitive sensing reference surface 202 also varies along its length.For example, distance (or depth) 216 is the closest that sensing element208 is to the capacitive sensing reference surface 202 while distance(or depth) 210 is the furthest that the upper surface of sensing element208 is from reference surface 202. The upper surface of sensing element208 increasingly slopes away from capacitive sensing reference surface202.

Within FIG. 2, note that distances 212 and 210 of sensing element 206are different than distances 216 and 218, respectively, of sensingelement 208. As such, when sensing elements 206 and 208 are coupled tosensing circuitry (e.g., 110), the proportional strength signalsprovided by them is unique as an object proximately located to sensingreference surface 202 travels along the length of sensing elements 206and 208. Therefore, the sensing circuitry can identify the spatiallocation of the object relative to the first axis of the capacitivesensing reference surface 202.

FIG. 3 is a side sectional view of an exemplary capacitive sensorpattern 300 in accordance with embodiments of the invention.Specifically, sensor pattern 300 includes sensing elements 310 and 320which can be utilized as part of a capacitive sensor apparatus (e.g.,100), such as but not limited to, a touchpad. When electrically coupledto sensing circuitry (e.g., 110), sensor pattern 300 providespositioning information which can be derived from which sensing elementdetects an object (e.g., a user's finger, a probe, and the like), andthe proportional strength of the signals on sensing elements 310 and320.

Sensing elements 310 and 320 can be twisted about a common axis. Forexample, FIG. 3A is a general cross sectional view at section 3A-3Ashowing sensing element 310 located above sensing element 320 while FIG.3B is a general cross sectional view at section 3B-3B showing sensingelement 310 located to the left of sensing element 320. Additionally,FIG. 3C is a general cross sectional view at section 3C-3C showingsensing element 310 located beneath sensing element 320 while FIG. 3D isa general cross sectional view at section 3D-3D showing sensing element310 located to the right of sensing element 320. And finally, FIG. 3E isa general cross sectional view at section 3E-3E showing sensing element310 located above sensing element 320. Note that since sections 3A-3Aand 3E-3E show sensing elements 310 and 320 similarly situated, it maybe desirable to have one of these sections outside the sensing region(e.g., 108) of a capacitive sensing apparatus in order to eliminate thepossibility of sensing circuitry receiving similar strength signals thatcorrespond to two different positions of sensor pattern 300.

Within FIG. 3, each of sensing elements 310 and 320 can have asubstantially constant width along its length and is configured to havevarying capacitive coupling to an object proximate to a capacitivesensing reference surface 302 along a first axis (e.g., X axis) of thereference surface 302. Note that the length of each of sensing elements310 and 320 can be oriented along the first axis. The sensing elements310 and 320 can be conductive, and are configured to provide informationcorresponding to a spatial location of the object relative to the firstaxis of the capacitive sensing reference surface 302. Sensing elements310 and 320 can separately provide the information corresponding to thespatial location of the object.

The capacitive coupling associated with sensing element 310 can varywith the varying distance of portions of sensing element 310 withrespect to the capacitive sensing reference surface 302. Additionally,the capacitive coupling associated with the sensing element 320 can varywith the varying distance of portions of sensing element 320 withrespect to the capacitive sensing reference surface 302. Note that thevarying distance of the portions of sensing element 310 are differentfrom the varying distance of the portions of sensing element 320. Thecapacitive coupling of sensing element 310 can include a first waveform(e.g., sinusoidal waveform) while the capacitive coupling of sensingelement 320 can include a second waveform (e.g., sinusoidal waveform).The capacitive coupling of sensing element 310 can include a first phasewhile the capacitive coupling of sensing element 320 can include asecond phase different from the first phase. For example, the capacitivecoupling of sensing element 310 can be 180 degrees out of phase with thecapacitive coupling of sensing element 320.

Note that any waveform mentioned herein with reference to embodiments inaccordance with the invention can be implemented in a wide variety ofways. For example, a waveform can be implemented as, but is not limitedto, a sinusoidal waveform, a triangular waveform, etc. It is appreciatedthat these exemplary waveforms are in no way an exhaustive listing ofwaveforms that can be implemented as part of embodiments in accordancewith the invention. It is noted that every continuous function can be awaveform in accordance with embodiments of the invention.

Within FIG. 3, each of sensing elements 310 and 320 can include a stripof conductive material. Additionally, the strip of conductive materialof sensing element 310 and the strip of conductive material of sensingelement 320 can be twisted about a common axis. Therefore, when sensingelement 310 is coupled with sensing circuitry (e.g., 110), it can havevarying capacitive coupling to an object proximate to the sensingreference surface 302 as the object moves along the length of sensingelement 310. As such, a different signal strength is provided by sensingelement 310 that is associated with each position or location along itslength. It is understood that when sensing element 320 is coupled withsensing circuitry (e.g., 110), it can operate in a manner similar tosensing element 310, as described above.

Specifically, sensing elements 310 and 320 of sensor pattern 300 can beembedded within a substrate material (e.g., 304). The distance (ordepth) 340 that sensing element 310 is separated from the capacitivesensing reference surface 302 varies along the length of sensing element310. Additionally, the distance (or depth) 330 that sensing element 320is separated from the capacitive sensing reference surface 302 variesalong the length of sensing element 320.

Within FIG. 3, since the conductive strips of sensing elements 310 and320 are twisted about a common axis, it is noted that depending on thelocation of sensing element 310, it can interfere with the capacitivecoupling with an object of sensing element 320 (and vice versa). Forexample, if an object was proximately located to reference surface 302at section 3A-3A, sensing element 310 would shield (or limit) thecapacitive coupling that sensing element 320 would have to the objectsince sensing element 310 is located between sensing element 320 and theobject. Alternatively, if the object was proximately located toreference surface 302 at section 3C-3C, sensing element 320 would shield(or limit) the capacitive coupling that sensing element 310 would haveto the object since sensing element 320 is located between sensingelement 310 and the object.

FIG. 4 is a side sectional view of an exemplary capacitive sensorpattern 400 in accordance with embodiments of the invention.Specifically, sensor pattern 400 includes sensing elements 410, 420, and430 which can be utilized as part of a capacitive sensor apparatus ordevice (e.g., 100), such as but not limited to, a touchpad. Whenelectrically coupled to sensing circuitry (e.g., 110), sensor pattern400 provides positioning information which can be derived from whichsensing element detects an object (e.g., a user's finger, a probe, andthe like), and the proportional strength of the signals on sensingelements 410, 420, and 430.

Sensing elements 410, 420, and 440 can be twisted about a common axis.For example, FIG. 4A is a general cross sectional view at section 4A-4Ashowing sensing element 430 located to the left of sensing element 420and sensing element 410 located above sensing elements 420 and 430. FIG.4B is a general cross sectional view at section 4B-4B showing sensingelement 410 located to the left of sensing element 420 and sensingelement 430 located beneath sensing elements 410 and 420. Additionally,FIG. 4C is a general cross sectional view at section 4C-4C showingsensing element 410 located to the left of sensing element 430 andsensing element 420 located above sensing elements 410 and 430. FIG. 4Dis a general cross sectional view at section 4D-4D showing sensingelement 420 located to the left of sensing element 430 and sensingelement 410 located beneath sensing elements 420 and 430. FIG. 4E is ageneral cross sectional view at section 4E-4E showing sensing element420 located to the left of sensing element 410 and sensing element 430located above sensing elements 410 and 420. FIG. 4F is a general crosssectional view at section 4F-4F showing sensing element 430 located tothe left of sensing element 410 and sensing element 420 located beneathsensing elements 410 and 430. And finally, FIG. 4G is a general crosssectional view at section 4G-4G showing sensing element 430 located tothe left of sensing element 420 and sensing element 410 located abovesensing elements 420 and 430. Note that since sections 4A-4A and 4E-4Eshow sensing elements 410, 420, and 430 similarly situated, it may bedesirable to have one of these sections outside the sensing region(e.g., 108) of a capacitive sensing apparatus (e.g., 100) in order toeliminate the possibility of sensing circuitry (e.g., 110) receivingsimilar strength signals that correspond to two different positions (orlocations) of sensor pattern 400.

Within FIG. 4, each of sensing elements 410, 420, and 430 has varyingdepth relative to a capacitive sensing reference surface 402 and aresubstantially parallel to each other. For example, sensing elements 420and 430 are substantially parallel to sensing element 410. Each ofsensing elements 410, 420, and 430 can have varying depth (or distance)relative to reference surface 402 and each can include a waveform.However, the waveform of sensing element 420 can be offset from thewaveform of sensing element 410 by one third of a period. Also, thewaveform of sensing element 430 can be offset from the waveform ofsensing element 410 by two thirds of a period. The sensing elements 410,420, and 430 can be configured to provide (e.g., sensing circuitry)information corresponding to a position of an object proximate to thecapacitive sensing reference surface 402 along a first axis of thecapacitive sensing reference surface 402. The sensing elements 410, 420,and 430 can each include a conductive trace. Portions of each of sensingelements 410, 420, and 430 can be configured to have a capacitivecoupling with respect to the object wherein the capacitive couplingvaries along the first axis.

Note that the position of the object can be determined using a signalcorresponding to sensing element 410, a signal corresponding to sensingelement 420, and a signal corresponding to sensing element 430. Thesensing elements 410, 420, and 430 can provide a cumulative outputsignal that is substantially constant at different locations along thesensing elements 410, 420, and 430. Each of sensing elements 410, 420,and 430 can include a strip of conductive material. Additionally, thestrip of conductive material of sensing element 410, the strip ofconductive material of sensing element 420, and the strip of conductivematerial of sensing element 430 can be twisted about a common axis.Therefore, when sensing element 410 is coupled with sensing circuitry(e.g., 110), it can have varying capacitive coupling to an objectproximate to the sensing reference surface 402 as the object moves alongthe length of sensing element 410. As such, a different signal strengthis provided by sensing element 410 that is associated with each positionor location along its length. It is appreciated that when sensingelements 420 and 430 are coupled with sensing circuitry (e.g., 110),they can operate in a manner similar to sensing element 410, asdescribed above.

There are a wide variety of ways for determining a location (orposition) of an object in relation to the length of sensor pattern 400using signals output by sensing elements 410, 420, and 430. Forinstance, FIG. 6 illustrates an exemplary signal strength chart 602along with its conversion into polar coordinates in accordance withembodiments of the invention. For example, suppose signal “A” isassociated with sensing element 410 (FIG. 4), signal “B” is associatedwith sensing element 420, and signal “C” is associated with sensingelement 430. As such, based on the signal strength shown within chart602, it can be determined that the object is located along sensor 400where sensing trace 420 is nearest to sensing surface 402, the sensingtrace 410 is the second nearest to sensing surface 402, and the sensingtrace 430 is the farthest from sensing surface 402. Therefore, withinthis example, the object is located on the right-hand side of thesection 4C-4C of sensor pattern 400.

More specifically, suppose signal “A” corresponds to sensing element410, signal “B” corresponds to sensing element 420, and signal “C”corresponds to sensing element 430, as mentioned above. And furthersuppose that sensing elements (or traces) 410, 420, and 430 have beenobserved to give values A₀, B₀, and C₀, respectively, when no object ispresent or near sensor pattern 400. As such, leta=A−A ₀,b=B−B ₀, andc=C−C ₀.Therefore, determination of the polar coordinates “h”, “r”, and angle θthat are associated with signals A, B, and C can be performed.

Within FIG. 6, it is noted that the value of “h” corresponds to theheight of the center of a circle 604 upon which points 606, 608, and 610can be located. The points 606, 608, and 610 are associated with signalsA, B, and C, respectively. The value of “r” corresponds to the radius ofcircle 604. The value of angle θ can be used to ascertain the linearlocation (or position) of an object in relationship (or proximity) tothe length of sensor pattern 400. Specifically, the value of height “h”can be determined by using the following relationship:h=(a+b+c)/3Once “h” has been determined, the radius “r” can then be determinedutilizing the following relationship:r=sqrt((⅔)×[(a−h)²+(b−h)²+(c−h)²])where “sqrt” represents the square root function. Once “r” has beendetermined, the angle θ can then be determined utilizing one of thefollowing relationships:θ=sin⁻¹((a−h)/r)ORθ=sin⁻¹((b−h)/r)ORθ=sin⁻¹((c−h)/r)Once the angle θ has been determined, it can then be converted into adistance that corresponds to a linear position measured along the lengthof sensor pattern 400 from one of its end points. For example, eachdegree of angle θ may be equal to a specific distance (e.g., a specificnumber of millimeters or inches) from one of the end points of sensorpattern 400. Alternatively, a lookup table may be utilized to ascertainthe distance that corresponds to the determined θ. It is noted that theangle θ can provide the location of the center of the object alongsensor pattern 400 while the “h” and the “r” can provide informationregarding the size of the object.

One of the advantages of determining the position along the first axis(e.g., X axis) of sensor pattern 400 in the manner described above isthat common-mode noise has no effect on the determination of “r” and θ.

Within FIG. 6, it is noted that angle θ can alternatively be determinedutilizing the following relationships:Cos θ=a−(b+c)/2Sin θ=sqrt(3)/2(b−c)θ=ATAN2(Cos θ, Sin θ)wherein “ATAN2” represents the arc tangent function. It is appreciatedthat the above three relationships may be more convenient for use with asmaller microprocessor.

Within FIG. 4, sensing elements 410, 420, and 430 of sensor pattern 400can be embedded within a substrate material (e.g., 404). For example,the distance (or depth) 440 that sensing element 420 is separated fromthe capacitive sensing reference surface 402 varies along the length ofsensing element 420. Additionally, the distance (or depth) 450 thatsensing element 430 is separated from the capacitive sensing referencesurface 402 varies along the length of sensing element 430. Note thatsensing element 410 can be implemented in a manner similar to sensingelements 420 and 430.

Since sensing elements 410, 420, and 430 are twisted about a commonaxis, it is noted that depending on their location, two of them caninterfere with the capacitive coupling with an object of the remainingsensing element. For example, if an object was proximately located toreference surface 402 at section 4D-4D, sensing elements 420 and 430would shield (or limit) the capacitive coupling that sensing element 410would have to the object since sensing element 420 and 430 are locatedbetween sensing element 410 and the object.

FIG. 5 is a side sectional view of an exemplary capacitive sensorpattern 500 in accordance with embodiments of the present invention.Specifically, sensor pattern 500 includes sensing elements 510 and 530which can be utilized as part of a capacitive sensor apparatus (e.g.,100), such as but not limited to, a touchpad. When electrically coupledto sensing circuitry (e.g., 110), sensor pattern 500 providespositioning information which can be derived from which sensing elementdetects an object (e.g., a user's finger, a probe, and the like), andthe proportional strength of the signals on sensing elements 510 and530.

Sensing elements 510 and 530 can be twisted about a mandrel 520 thatprovides them a common axis. For example, FIG. 5A is a general crosssectional view at section 5A-5A showing sensing element 510 locatedabove mandrel 520 which is located above sensing element 530. FIG. 5B isa general cross sectional view at section 5B-5B showing sensing element510 located to the left of mandrel 520 and sensing element 530 locatedto the right of mandrel 520. Additionally, FIG. 5C is a general crosssectional view at section 5C-5C showing sensing element 510 locatedbeneath mandrel 520 which is located beneath sensing element 530. FIG.5D is a general cross sectional view at section 5D-5D showing sensingelement 510 located to the right of mandrel 520 and sensing element 530located to the left of mandrel 520. FIG. 5E is a general cross sectionalview at section 5E-5E showing sensing element 510 located above mandrel520 which is located above sensing element 530. Note that since sections5A-5A and 5E-5E show mandrel 520 and sensing elements 510 and 530similarly situated, it may be desirable to have one of these sectionsoutside the sensing region (e.g., 108) of a capacitive sensing apparatus(e.g., 100) in order to eliminate the possibility of sensing circuitry(e.g., 110) receiving similar strength signals that correspond to twodifferent positions of sensor pattern 500.

Within FIG. 5, each of sensing elements 510 and 530 can have asubstantially constant width along its length and is configured to havevarying capacitive coupling to an object proximate to a capacitivesensing reference surface 502 along a first axis (e.g., X axis) of thereference surface 502. Note that the length of each of sensing elements510 and 530 can be oriented along the first axis (e.g., mandrel 520).The sensing elements 510 and 530 can be conductive, and are configuredto provide information corresponding to a spatial location of the objectrelative to the first axis of the capacitive sensing reference surface502. Sensing elements 510 and 530 can separately provide the informationcorresponding to the spatial location of the object.

The capacitive coupling associated with sensing element 510 can varywith the varying distance of portions of sensing element 510 withrespect to the capacitive sensing reference surface 502. Additionally,the capacitive coupling associated with the sensing element 530 can varywith the varying distance of portions of sensing element 530 withrespect to the capacitive sensing reference surface 502. Note that thevarying distance of the portions of sensing element 510 are differentfrom the varying distance of the portions of sensing element 530. Thecapacitive coupling of sensing element 510 can include a first waveform(e.g., sinusoidal waveform) while the capacitive coupling of sensingelement 530 can include a second waveform (e.g., sinusoidal waveform).Note that every continuous function can be a waveform. The capacitivecoupling of sensing element 510 can include a first phase while thecapacitive coupling of sensing element 530 can include a second phasedifferent from the first phase. For example, the capacitive coupling ofsensing element 510 can be 180 degrees out of phase with the capacitivecoupling of sensing element 530, but is not limited to such.

Within FIG. 5, each of sensing elements 510 and 530 can include a stripof conductive material. Additionally, the strip of conductive materialof sensing element 510 and the strip of conductive material of sensingelement 530 can be twisted about mandrel 520. Therefore, when sensingelement 510 is coupled with sensing circuitry (e.g., 110), it can havevarying capacitive coupling to an object proximate to the sensingreference surface 502 as the object moves along the length of sensingelement 510. As such, a different signal strength is provided by sensingelement 510 that is associated with each position or location along itslength. It is understood that when sensing element 530 is coupled withsensing circuitry (e.g., 110), it can operate in a manner similar tosensing element 510, as described above.

Specifically, sensing elements 510 and 530 of sensor pattern 500 can beembedded within a substrate material (e.g., 508). The distance (ordepth) 506 that sensing element 510 is separated from the capacitivesensing reference surface 502 varies along the length of sensing element510. Additionally, the distance (or depth) 504 that sensing element 530is separated from the capacitive sensing reference surface 502 variesalong the length of sensing element 530.

Within FIG. 5, since the conductive strips of sensing elements 510 and530 are twisted about mandrel 520, it is noted that depending on thelocation of sensing element 510, it and mandrel 520 can interfere withthe capacitive coupling with an object of sensing element 530 (and viceversa). For example, if an object was proximately located to referencesurface 502 at section 5A-5A, sensing element 510 and mandrel 520 wouldshield (or limit) the capacitive coupling that sensing element 530 wouldhave to the object since sensing element 510 and mandrel 520 are locatedbetween sensing element 530 and the object. Alternatively, if the objectwas proximately located to reference surface 502 at section 5C-5C,sensing element 530 and mandrel 520 would shield (or limit) thecapacitive coupling that sensing element 510 would have to the objectsince sensing element 530 and mandrel 520 are located between sensingelement 510 and the object.

FIGS. 7A-7E are described in combination in order to provide a betterunderstanding of an exemplary capacitive sensor pattern 700 a, inaccordance with embodiments of the invention. Specifically, FIG. 7A is across sectional view of capacitive sensor pattern 700 a in accordancewith embodiments of the invention. Additionally, FIGS. 7B, 7C, 7D, 7Eare lengthwise side sectional views 700 b, 700 c, 700 d, and 700 e,respectively, of capacitive sensor pattern 700 a in accordance withembodiments of the invention.

Sensor pattern 700 a includes sensing elements 706, 708, 710, and 712which can be utilized as part of a two-dimensional capacitive sensorapparatus (e.g., 100), such as but not limited to, a touchpad. Whenelectrically coupled, sensor pattern 700 a provides positioninginformation from a sensor pattern that has substantially parallel traces(or elements) with no crossovers. The positioning information can bederived from which sensing element or elements detect an object (e.g., auser's finger, a probe, and the like) proximate to a sensing referencesurface 702, and the proportional strength of the signals on sensingelements 706, 708, 710, and 712.

Specifically, capacitive sensor pattern 700 a can include an insulatingsubstrate material 704 having a substantially smooth, planar capacitivesensing reference surface 702 where an object (e.g., a user's finger, aprobe, and the like) can contact or be proximately located thereto. Thesubstrate 704 includes substantially parallel channels (or grooves) 730,732, 734, and 736. Along the length of each of channels 732, 734, and736 can include an undulating waveform surface that varies in distance(or depth) from reference surface 702. Additionally, channels 732, 734,and 736 can be implemented to include three phases. However, along thelength of groove 730, its distance from reference surface 702 can besubstantially constant. A conductive material can be deposited withinchannels 730, 732, 734, and 736 to produce sensing elements 706, 708,710, and 712, respectively. Therefore, sensing elements 710, 712, and708 can each include a waveform that varies in distance from referencesurface 702 as shown in FIGS. 7B, 7C, and 7D, respectively. When coupledto sensing circuitry (e.g., 110), sensing elements (or traces) 708, 710,and 712 can be used to determine a position of an object relative to afirst axis (e.g., X axis) of the sensing reference surface 702 whilesensing element 706 can be used to determine a position of the objectrelative to a second axis (e.g., Y axis) of the reference surface 702.The second axis may be non-parallel (e.g., substantially perpendicular)to the first axis.

Within FIGS. 7A-7E, a conductive material can be deposited withinchannels 730, 732, 734, and 736 to produce sensing elements 706, 708,710, and 712, respectively. Within one embodiment, each of sensingelements 708, 710, and 712 can be disposed above substrate 704, whereinthe varying depths of channels 732, 734, and 736 define a unique depth(or distance) profile for each of sensing elements 708, 710, and 712,respectively. The deposition of the conductive material may beimplemented in a wide variety of ways (e.g., printing, spraying on,painting on, and the like). The sensing elements 706, 708, 710, and 712can be formed by the deposition of any one conductive material or mayinclude layers of conductive materials such as, but not limited to,black chrome, aluminum, titanium, and the like. Although the foregoingmaterials are mentioned specifically, it is understood that anyconductive material that can be deposited into channels 730, 732, 734,and 736 to form sensing elements 706, 708, 710, and 712, respectively,can be used.

Sensing elements (or traces) 708, 710, and 712 have varying depths 722,724, and 726, respectively, with respect to sensing reference surface702. However, sensing element (or trace) 706 has a substantiallyconstant depth 720 with respect to sensing reference surface 702. Inaccordance with one embodiment, sensing elements 708, 710, and 712 eachincludes a waveform having varying depth (or distance) from referencesurface 702, each of which has a different phase. For example, withinthe present embodiment, if the waveform shape of conductive trace 708 issubstantially equal to sin θ, then the waveform shape of conductivetrace 710 may be substantially equal to sin (θ+120 degrees), while thewaveform shape of conductive trace 712 may be substantially equal to sin(θ+240 degrees). Alternatively, the waveform of sensing element 710 maybe offset (or shifted) from the waveform of conductive trace 708 by 2π/3radians while the waveform of sensing element 712 may be offset (orshifted) from the waveform of conductive trace 708 by 4π/3 radians. Inanother embodiment, the waveform of sensing element 710 can be offsetfrom the waveform of sensing element 708 by one third of a period whilethe waveform of sensing element 712 can be offset from the waveform ofsensing element 708 by two thirds of a period. However, it is understoodthat the phase and shape of the waveform of sensing elements 708, 710,and 712 are not in any way limited to the present embodiment or therecited embodiments.

Within FIG. 7A-7E, it is understood that the position of the object canbe determined using a signal corresponding to sensing element 708, asignal corresponding to sensing element 710, and a signal correspondingto sensing element 712. The sensing elements 708, 710, and 712 canprovide a cumulative output signal that is substantially constant atdifferent locations along the sensing elements 708, 710, and 712. Thereare a wide variety of ways for determining a location (or position) ofan object in relation to the length of sensor pattern 700 a usingsignals output by sensing elements 708, 710, and 712. For example, thedetermination of the location (or position) of an object in relation tothe length of sensor pattern 700 a can be implemented in a mannersimilar to that described herein with reference to FIGS. 4 and 6, but isnot limited to such.

Note that capacitive sensor pattern 700 a may have been fabricatedutilizing a process 1600 of FIG. 16 described below, or by otherprocesses (e.g., that may include machining an insulating material withthe desired depth variations).

FIG. 8 is a plan view of an exemplary capacitive sensor pattern 800including electrical connections, in accordance with embodiments of theinvention. Specifically, sensor pattern 800 includes four repeating setsof sensing elements 706, 708, 710, and 712. Note that sensing elements708, 710, and 712 can each have varying depth (or distance) from thesensing reference surface (not shown) while sensing element 706 can havea substantially constant depth (or distance) from the sensing referencesurface. The sensing elements 708, 710, and 712 can include waveformsthat have three phases, but are not limited to such.

Within the present embodiment, each of sensing elements 708 is coupledwith electrical trace 810, each of sensing elements 710 is coupled withtrace 820, and each of sensing elements 712 is coupled with trace 830.However, each of sensing elements 706 is coupled independently withtraces 840. Traces 810, 820, 830, and 840 can be coupled with traces 104and/or 106 of FIG. 1. When coupled in this manner, the sensor pattern800 can be utilized to form the sensing region 108. Sensing elements708, 710, and 712 can be used to determine the x-position, or first axislocation, of an object (e.g., a finger, a probe, a stylus, etc.)relative to sensor pattern 800. Sensing elements 706 can be used todetermine the y-position, or second axis location, of an object (e.g., afinger, a probe, a stylus, etc.) relative to sensor pattern 800.

In another embodiment, each of sensing elements 708, 710, and 712 can becoupled independently with sensing circuitry (e.g., 110), in which casethe y-position of an object could be determined directly from eachtrace. As such, each sensing element 706 may be excluded from sensorpattern 800. This method of electrically coupling each of traces 708,710, and 712 of sensor pattern 800 independently may involve more thanone Application Specific Integrated Circuit (ASIC) if the number ofsensing elements is large, whereas the method of interconnecting allsensing elements having the same varying depth and phase, then usingintermediate sensing elements 706 to determine the y-position allows alarger number of sensing elements to be used in conjunction with asingle ASIC.

Within FIG. 8, the sensor pattern 800 can also be implemented with guardtrace 850 at the “top” and guard trace 852 at the “bottom” of sensorpattern 800, thereby enabling the “edge” sensing elements located nearthem to operate in a manner similar to those sensing elements morecentrally located within the sensor pattern 800. The guard traces 850and 852 may be electrically driven, grounded and/or held at asubstantially fixed or constant potential in accordance with embodimentsof the present invention.

For example, guard traces 850 and 852 of FIG. 8 may be coupled to groundvia traces 854 and 856, respectively; in this manner, guard traces 850and 852 are functioning as grounded traces. Alternatively, guard traces850 and 852 may be coupled to a constant potential signal via traces 854and 856, respectively; in this manner, guard traces 850 and 852 arefunctioning as constant potential traces. Guard traces 850 and 852 mayalso be actively driven via traces 854 and 856, respectively; in thismanner, guard traces 850 and 852 are functioning as driven guard traces.It is understood that guard traces 850 and 852 may be implemented in awide variety of ways.

Noted that one or more guard traces (or grounded or fixed potentialtraces) similar to guard traces 850 and 852 can also be included as partof or with any sensing pattern described herein.

Although sensor pattern 800 of FIG. 8 indicates using repeated sets ofthree sensing elements to determine the x-position (e.g., first axis) ofan object relative to sensor pattern 800, it should be understood that adifferent number of sensing elements may be employed, using anappropriate mathematical relationship, to discern the x-position of anobject.

FIG. 9 is a plan view of an exemplary sensor pattern 900 in accordancewith embodiments of the invention. Sensor pattern 900 includes sixrepeated patterns of sensing elements 708, 710, and 712. Specifically,sensing elements 708, 710, and 712 can each have varying depth (ordistance) from the sensing reference surface (not shown). The sensingelements 708, 710, and 712 can include waveforms having three phases.Sensing elements 708, 710, and 712 can be utilized as part of a singlelayer capacitive sensor apparatus (e.g., 100), such as but not limitedto, a touchpad. When electrically coupled, sensor pattern 900 canprovide two-dimensional positioning information that has substantiallyparallel traces (or sensing elements) with no crossovers. The sensorpattern 900 can be utilized in any manner similar to that describedherein, but is not limited to such.

It is noted that the six repeated patterns of sensing elements 708, 710,and 712 can operate in any manner similar to sensing elements 708, 710,and 712 of sensor pattern 800 of FIG. 8, described herein.

FIGS. 10A and 10B are side sectional views of an exemplary capacitivesensor pattern 1000 in accordance with embodiments of the invention.Specifically, sensor pattern 1000 includes sensing elements 1020 and1022 which can be utilized as part of a capacitive sensor apparatus(e.g., 100) such as, but not limited to, a touchpad. When electricallycoupled to sensing circuitry (e.g., 110), sensor pattern 1000 providespositioning information which can be derived from which sensing elementdetects an object (e.g., a user's finger, a probe, and the like), andthe proportional strength of the signals on sensing elements 1020 and1022.

Each of sensing elements 1020 and 1022 can have a substantially constantwidth along its length and is configured to have varying capacitivecoupling to an object proximate to a capacitive sensing referencesurface 1002 along a first axis (e.g., X axis) of the reference surface1002. Specifically, the capacitive coupling of sensing element 1020 canvary with variations in dielectric constant between the capacitivesensing reference surface 1002 and portions of sensing element 1020.Furthermore, the capacitive coupling of sensing element 1022 can varywith variations in dielectric constant between the capacitive sensingreference surface 1002 and portions of sensing element 1022. It isappreciated that the variations in the dielectric constant for sensingelement 1020 can be different from the variations in the dielectricconstant for sensing element 1022. Therefore, sensing elements 1020 and1022 can each have a substantially constant depth (or distance) from thesensing reference surface 1002, while each can be configured to havevarying capacitive coupling to an object proximate to sensing referencesurface 1002.

Within FIGS. 10A and 10B, the length of each of sensing elements 1020and 1022 can be oriented along the first axis. The sensing elements 1020and 1022 can be conductive, and are configured to provide informationcorresponding to a spatial location of the object relative to the firstaxis of the capacitive sensing reference surface 1002. Note that sensingelements 1020 and 1022 can separately provide the informationcorresponding to a spatial location of the object.

Each of sensing elements 1020 and 1022 can include a strip of conductivematerial that is substantially straight along the first axis.Specifically, within FIG. 10A, sensing element 1020 is disposed above asubstrate 1008, while a dielectric material 1006 is disposed abovesensing element 1020, and a dielectric material 1004 is disposed abovedielectric material 1006. Note that the upper surface of dielectricmaterial 1006 increasingly slopes away from capacitive sensing referencesurface 1002. Given that dielectric material 1004 has a lower dielectricconstant than dielectric material 1006 and sensing element 1020 iscoupled to sensing circuitry (e.g., 110), sensing element 1020 can havea stronger capacitive coupling to an object proximate to the left-handside of capacitive sensing reference surface 1002 than when proximate toits right-hand side. Therefore, when sensing element 1020 is coupledwith sensing circuitry (e.g., 110), it can have varying capacitivecoupling to an object proximate to the sensing reference surface 1002 asthe object moves along the length of sensing element 1020. As such, adifferent signal strength is provided by sensing element 1020 that isassociated with each position or location along its length.

Within FIG. 10B, sensing element 1022 is disposed above substrate 1008,while a dielectric material 1010 is disposed above sensing element 1022,and a dielectric material 1012 is disposed above dielectric material1010. Note that the upper surface of dielectric material 1010increasingly slopes away from capacitive sensing reference surface 1002.Given that dielectric material 1010 has a lower dielectric constant thandielectric material 1012 and sensing element 1022 is coupled to sensingcircuitry (e.g., 110), sensing element 1022 can have a strongercapacitive coupling to an object proximate to the left-hand side ofcapacitive sensing reference surface 1002 than when proximate to itsright-hand side. Therefore, when sensing element 1022 is coupled withsensing circuitry (e.g., 110), it can have varying capacitive couplingto an object proximate to the sensing reference surface 1002 as theobject moves along the length of sensing element 1022. As such, adifferent signal strength is provided by sensing element 1022 that isassociated with each position or location along its length.

Within FIGS. 10A and 10B, note that dielectric materials 1004, 1006,1010, and 1012 can be implemented with differing dielectric constants.As such, when sensing elements 1020 and 1022 are coupled to sensingcircuitry (e.g., 110), the proportional strength signals provided bythem can be unique as an object proximately located to sensing referencesurface 1002 travels along the length of sensing elements 1020 and 1022.Therefore, the sensing circuitry can identify the spatial location ofthe object relative to the first axis of the capacitive sensingreference surface 1002.

FIG. 11 is a plan view of an exemplary loop capacitive sensor pattern1100 in accordance with embodiments of the invention. Specifically,sensor pattern 1100 includes three sets of concentric loop patterns ofsensing elements 708 a, 710 a, and 712 a that can include waveformshaving three phases. The sensor pattern 1100 can be utilized as part ofa single layer capacitive sensor apparatus (e.g., 100), such as but notlimited to, a touch pad. When electrically coupled, sensor pattern 1100can provide continuous two-dimensional positioning information that hassensing elements with varying depth and no crossovers. The sensorpattern 1100 can be utilized in any manner similar to that describedherein, but is not limited to such.

Specifically, each of the sensing elements 708 a, 710 a, and 712 a hasvarying depth (or distance) from the sensing reference surface (notshown) and form a substantially circular (or loop) pattern. Noted that aloop pattern may include any closed loop sensor pattern shape (e.g.,circle, square, rectangle, triangle, polygon, radial arc sensor pattern,curve, a semi-circle sensor pattern, and/or any sensor pattern that isnot substantially in a straight line or in a non-linear manner). Thesensing elements 708 a, 710 a, and 712 a are not required to overlapeach other in order to determine an angular position φ of an objectrelative to the substantially circular pattern (e.g., loop) in atwo-dimensional space. It is noted that the angular position φ starts atan origin 1102 which can be located anywhere associated with sensorpattern 1100. The sensing elements 708 a, 710 a, and 712 a can provide acumulative output signal that is substantially constant at differentlocations along the sensing elements 708 a, 710 a, and 712 a.

Within FIG. 11, the sensing elements 708 a, 710 a, and 712 a can eachinclude a conductive trace. Furthermore, each set of sensing elements(e.g., 708 a, 710 a, and 712 a) can be used for determining a radialposition “R” of the object relative to the loop in the two-dimensionalspace.

Each of the sensing elements (e.g., 708 a, 710 a, and 712 a) of thesensor pattern 1100 can be individually coupled with sensing circuitry(e.g., 110) utilizing conductive coupling traces (e.g., 104 and/or 106).When coupled in this manner, the sensor pattern 1100 can be utilized toform a sensing region (e.g., 108). Furthermore, when coupled in thismanner, sensor pattern 1100 can provide positioning information alongthe angular position φ and the radial position “R”.

Alternatively, all similar sensing elements (e.g., 712 a) of sensorpattern 1100 can be coupled together as shown in FIG. 8 and coupled withsensing circuitry (e.g., 110) utilizing a conductive coupling trace(e.g., 104 or 106). When coupled in this manner, the sensor pattern 1100can provide positioning information to the sensing circuitrycorresponding to the angular position φ, but not of the radial position“R”. It is understood that the radial position “R” can be determined inany manner similar to the way the second axis position can bedetermined, as described herein.

Sensor pattern 1100 can be implemented with a greater or lesser numberof sensing elements than shown within the present embodiment. Forexample, sensor pattern 1100 can be implemented with a single set ofsensing elements 708 a, 710 a, and 712 a. Alternatively, sensor pattern1100 can be implemented with multiple sets of sensing elements 708 a,710 a, and 712 a. Sensor pattern 1100 and its sensing elements can beimplemented in any manner similar to that described herein, but is notlimited to such.

Within FIG. 11, each set of the sensing elements (e.g., 708 a, 710 a,and 712 a) of sensor pattern 1100 can operate in any manner similar tothat described herein in order to provide the positioning informationcorresponding to the angular position φ of an object (e.g., a user'sfinger, a probe, a stylus, and the like) in relation to sensor pattern1100. The sensing elements 708 a, 710 a, and 712 a can be configured toprovide information corresponding to a spatial location of the objectproximate to a curve on the capacitive sensing reference surface (notshown). For example, each set of the signals associated with a set ofsensing elements (e.g., 708 a, 710 a, and 712 a) can be utilized todetermine the phase angle θ, in a manner similar to that describedherein with reference to FIG. 6. Noted that once the phase angle φ hasbeen determined, it may be converted into a geometric position angle φrelative to the origin 1102. In this manner, the angular position φ ofan object is determined relative to sensor pattern 1100.

FIG. 12 illustrates an exemplary loop capacitive sensor pattern 1200 inaccordance with embodiments of the present invention. Specifically,sensor pattern 1200 includes three sets of concentric loop patterns ofsensing elements 706 b, 708 b, 710 b, and 712 b. Note that sensingelements 708 b, 710 b, and 712 b can each have varying depth (ordistance) from the sensing reference surface (not shown) while sensingelement 706 b can have a substantially constant depth from the referencesurface. The sensing elements 708 b, 710 b, and 712 b can includewaveforms having three phases. Sensor pattern 1200 can be utilized aspart of a single layer capacitive sensor apparatus (e.g., 100), such as,but not limited to, a touch pad. When electrically coupled, sensorpattern 1200 can provide continuous two-dimensional positioninginformation that has sensing elements with varying depth and nocrossovers. The sensor pattern 1200 can be utilized in any mannersimilar to that described herein, but is not limited to such.

Specifically, sensing elements 706 b, 708 b, 710 b, and 712 b form asubstantially circular (or loop) pattern. Noted that a loop pattern mayinclude any closed loop sensor pattern shape (e.g., circle, square,rectangle, triangle, polygon, radial arc sensor pattern, a semi-circlesensor pattern, and/or any sensor pattern that is not substantially in astraight line). The sensing elements 706 b, 708 b, 710 b, and 712 b arenot required to overlap each other in order to determine an angularposition φ and radial position “R” of an object relative to thesubstantially circular pattern (e.g., loop) in a two-dimensional space.The angular position φ starts at an origin 1202 which can be locatedanywhere associated with sensor pattern 1200. The sensing elements 708b, 710 b, and 712 b provide a cumulative output signal that can besubstantially constant at different locations along the sensing elements708 b, 710 b, and 712 b.

Within FIG. 12, the sensing elements 706 b, 708 b, 710 b, and 712 b caneach include a conductive trace. Similar varying depth sensing elements(e.g., 708 b) of sensor pattern 1200 can be coupled together as shown inFIG. 8 and coupled with sensing circuitry (e.g., 110) utilizing aconductive coupling trace (e.g., 104 or 106). When coupled in thismanner, the sensor pattern 1200 can provide positioning information tothe sensing circuitry corresponding to the angular position φ, but notof the radial position “R”. It is understood that the radial position“R” can be determined from sensors 706 b in any manner similar to theway the second axis position can be determined, as described herein.

Sensor pattern 1200 can be implemented with a greater or lesser numberof sensing elements than shown within the present embodiment. Forexample, sensor pattern 1200 can be implemented with a single set ofsensing elements 706 b, 708 b, 710 b, and 712 b. Alternatively, sensorpattern 1200 can be implemented with multiple sets of sensing elements706 b, 708 b, 710 b, and 712 b. Sensor pattern 1200 and its sensingelements can be implemented in any manner similar to that describedherein, but is not limited to such.

Within FIG. 12, each set of the varying depth sensing elements 706 b,708 b, 710 b, and 712 b of sensor pattern 1200 can operate in any mannersimilar to that described herein in order to provide the positioninginformation corresponding to the angular position φ of an object (e.g.,a user's finger, a probe, a stylus, and the like) in relation to sensorpattern 1200. For example, each set of the signals associated with theset of varying depth sensing elements 708 b, 710 b, and 712 b can beutilized to determine the phase angle θ, in a manner similar to thatdescribed herein with reference to FIG. 6. Noted that once the phaseangle θ has been determined, it may be converted into a geometricposition angle φ relative to the origin 1202. In this manner, theangular position φ of an object is determined relative to sensor pattern1200.

FIG. 13 is a plan view of an exemplary loop capacitive sensor pattern1300 in accordance with embodiments of the invention. Specifically,sensor pattern 1300 includes three sets of concentric loop patterns ofsensing elements 708 c, 710 c and 712 c. Note that sensing elements 708c, 710 c, and 712 c can each have varying depth or distance from thereference surface (not shown). The sensing elements 708 c, 710 c, and712 c can be implemented to include waveforms having three phases. Thesensing elements 708 c, 710 c, and 712 c can be utilized as part of asingle layer capacitive sensor apparatus (e.g., 100), such as but notlimited to, a touchpad. When electrically coupled, sensor pattern 1300can provide continuous two-dimensional positioning information that hassensing elements with varying depth and no crossovers. The sensorpattern 1300 can be utilized in any manner similar to that describedherein, but is not limited to such.

Note that sensor pattern 1300 can operate in any manner similar tosensor pattern 1100 of FIG. 11. The sensor pattern 1300 can beimplemented with a greater or lesser number of sensing elements thanshown within the present embodiment. Sensor pattern 1300 and its sensingelements can be implemented in any manner similar to that describedherein, but is not limited to such.

FIG. 14 is a plan view of an exemplary loop capacitive sensor pattern1400 in accordance with embodiments of the invention. Specifically,sensor pattern 1400 includes two sets of concentric loop patterns ofsensing elements 706 d, 708 d, 710 d, and 712 d. Note that sensingelements 708 d, 710 d, and 712 d can each have varying depth or distancefrom the reference surface (not shown) while sensing element 706 d canhave a substantially constant depth or distance from the referencesurface. The sensing elements 708 d, 710 d, and 712 d can be implementedto include waveforms in three phases. The sensing elements 706 d, 708 d,710 d, and 712 d can be utilized as part of a capacitive sensorapparatus (e.g., 100), such as but not limited to, a touchpad. Whenelectrically coupled, sensor pattern 1400 can provide continuoustwo-dimensional positioning information that has sensing elements withvarying depth and no crossovers. The sensor pattern 1400 can be utilizedin any manner similar to that described herein, but is not limited tosuch.

It is appreciated that sensor pattern 1400 can operate in any mannersimilar to sensor patterns 1100 (FIG. 11) and/or 1200 (FIG. 12). Thesensor pattern 1400 can be implemented with a greater or lesser numberof sensing elements than shown within the present embodiment. Sensorpattern 1400 and its sensing elements can be implemented in any mannersimilar to that described herein, but is not limited to such.

FIG. 15 is a plan view of an exemplary “fishbone” capacitive sensorpattern 1500 in accordance with embodiments of the invention.Specifically, sensor pattern 1500 includes a set of sensing elements 708e, 710 e, and 712 e that can be utilized as part of a capacitive sensorapparatus (e.g., 100), such as but not limited to, a touchpad. Note thatsensing elements 708 e, 710 e, and 712 e can each have varying depth (ordistance) from a sensing reference surface (not shown). Whenelectrically coupled, sensor pattern 1500 can provide two-dimensionalpositioning information that has substantially parallel traces (orsensing elements) with no crossovers. The sensor pattern 1500 can beutilized in any manner similar to that described herein with referenceto FIGS. 7A-7E, 8, and 9, but is not limited to such. Moreover, sensorpattern 1500 can be utilized in any manner similar to that describedherein, but is not limited to such.

Specifically, sensing element 708 e can include a plurality ofextensions 1502 that are substantially parallel to each other and aresubstantially perpendicular to a first axis of sensing element 708 e.The sensing element 710 e can include a plurality of extensions 1504that are substantially parallel to each other and are substantiallyperpendicular to the first axis of sensing element 710 e. The sensingelement 712 e can include a plurality of extensions 1506 that aresubstantially parallel to each other and are substantially perpendicularto the first axis of sensing element 712 e.

Within FIG. 15, the plurality of extensions 1502 of sensing element 708e can be interdigitated with the plurality of extensions 1504 of sensingelement 710 e. Moreover, the plurality of extensions 1506 of sensingelement 712 e can be interdigitated with the plurality of extensions1504 of sensing element 710 e.

Sensing elements 708 e, 710 e, and 712 e can be used for determining afirst location of an object (e.g., a user's finger, a probe, a stylus,and the like) in relation to sensor pattern 1500 along the first axis ofa two-dimensional space. Furthermore, a repeated set of sensing elements708 e, 710 e, and 712 e (not shown) can be used for determining firstand second locations of an object in relation to sensor pattern 1500along the first axis and a second axis of the two-dimensional space,wherein the second axis is substantially non-parallel (or substantiallyperpendicular) to the first axis.

Within FIG. 15, sensor pattern 1500 can operate in any manner similar tosensor patterns 700 a-700 e of FIGS. 7A-E. Additionally, the sensorpattern 1500 can be implemented with a greater or lesser number ofsensing elements than shown within the present embodiment. Sensorpattern 1500 and its sensing elements can be implemented in any mannersimilar to that described herein, but is not limited to such.

FIG. 16 is a flowchart of a method 1600 for establishing aposition-varying capacitive coupling between a conductive objectproximate to a capacitive sensing reference surface and a conductivetrace in accordance with embodiments of the invention. Although specificoperations are disclosed in method 1600, such operations are exemplary.That is, method 1600 may not include all of the operations illustratedby FIG. 16. Alternatively, method 1600 may include various otheroperations and/or variations of the operations shown by FIG. 16.

Specifically, a plurality of channel patterns can be provided (orformed) in a substrate. Note that the channel patterns varying in depth.A conductive material can be deposited onto the channel patterns to forma first sensing element and second sensing element. The first sensingelement and second sensing element can be conductive and liesubstantially along a first orientation. Furthermore, each of the firstsensing element and second sensing element can be configured to provideinformation corresponding to a first location along the firstorientation.

At operation 1610 of FIG. 16, a plurality of channel (or groove)patterns having varying depth can be provided (or formed) in asubstrate. It is understood that the substrate can be implemented in awide variety of ways. For example, the substrate can be implemented toinclude, but is not limited to, a plastic or a crystalline material.Additionally, the substrate can be implemented as a component of aninformation display device or a portable computing device. For example,the substrate can be implemented as a part of a casing or front cover ofan information display device or portable computing device. The channelpatterns can include waveforms or portions of waveforms. For example,the channel patterns can include one or more sinusoidal waveforms.Alternatively, the channel patterns can include one or more portions ofa sinusoidal waveform.

At operation 1620, a conductive material can be deposited onto thechannel (or groove) patterns to form a first sensing element and secondsensing element that are conductive and lie substantially along a firstorientation. Note that more than two sensing elements can be formed atoperation 1620. Each of the first sensing element and second sensingelement can be configured to provide information corresponding to afirst location along the first orientation. Note that the firstorientation can be implemented in diverse ways. For example, the firstorientation can be substantially linear. Alternatively, the firstorientation can be non-linear. The first and second sensing elements canbe implemented in a wide variety of ways. For example, the first sensingelement can include a first waveform while the second sensing elementcan include a second waveform. Additionally, the first waveform and thesecond waveform can be different or similar. The first waveform and thesecond waveform can each include one or more sinusoidal waveforms or aportion of a sinusoidal waveform. Moreover, the first waveform and thesecond waveform can each have a different phase. It is understood thatthe first sensing element and second sensing element can each form atleast a portion of a loop or a curve.

At operation 1630 of FIG. 16, the first sensing element can bebackfilled with a material. Note that the second sensing element mayalso be backfilled with a material at operation 1630. Note that thebackfilling material can be implemented in a wide variety of ways. Forexample, the material can be implemented as, but not limited to, thematerial of which the substrate is formed, insulting material, and/orelectrical shielding material. This optional backfilling material canprovide physical protection to the one or more sensing elements.Additionally, the backfilling material can provide electrical shieldingthereby causing the one or more sensing elements to measure capacitanceon a desired reference sensing surface of the substrate, instead of onboth sides of the substrate. Moreover, the backfilling material canprovide a smooth back surface on the substrate that may be desirable insome circumstances.

By fabricating the capacitive sensor pattern in the manner shown in FIG.16, failure rates can be reduced since only one layer of conductivematerial is utilized, and there are no crossovers in the sensingelements. In addition, the capacitive sensor pattern may be manufacturedvery inexpensively by molding the channel patterns into the case of alaptop computer or other electronic device and depositing (or printingor spraying) the conductive material onto the channel patterns.

Note that sensor patterns in accordance with embodiments of theinvention do not induce signal to noise ratio concerns.

The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical application,to thereby enable others skilled in the art to best utilize theinvention and various embodiments with various modifications as aresuited to the particular use contemplated. It is intended that the scopeof the invention be defined by the Claims appended hereto and theirequivalents.

What is claimed is:
 1. A capacitive sensor apparatus comprising: a firstsensing element having a length oriented along a first axis of acontactable capacitive sensing reference surface, said first sensingelement having substantially constant diameter along its length andconfigured to have varying capacitive coupling, along said first axis,to an object proximate to said contactable capacitive sensing referencesurface; and a second sensing element having a length oriented alongsaid first axis, said second sensing element having substantiallyconstant diameter along its length and configured to have varyingcapacitive coupling, along said first axis, to said object proximate tosaid contactable capacitive sensing reference surface, wherein saidfirst sensing element and said second sensing element are conductive,and are configured to provide information corresponding to a spatiallocation of said object relative to said first axis.
 2. The capacitivesensor apparatus of claim 1, wherein said capacitive coupling associatedwith said first sensing element varies with varying distance of portionsof said first sensing element to said contactable capacitive sensingreference surface.
 3. The capacitive sensor apparatus of claim 2,wherein said capacitive coupling associated with said second sensingelement varies with varying distance of portions of said second sensingelement to said contactable capacitive sensing reference surface, saidvarying distance of said portions of said first sensing elementdifferent from said varying distance of said portions of said secondsensing element.
 4. The capacitive sensor apparatus of claim 3, whereinsaid first sensing element and said second sensing element eachcomprises a strip of conductive material.
 5. The capacitive sensorapparatus of claim 4, wherein said strip of conductive material of saidfirst sensing element is substantially straight and decreases indistance relative to said capacitance sensing surface along said firstaxis, and wherein said strip of conductive material of said secondsensing element is substantially straight and increases in distancerelative to said capacitance sensing surface along said first axis. 6.The capacitive sensor apparatus of claim 1, wherein: said varyingcapacitive coupling of said first sensing element comprises a firstwaveform; and said varying capacitive coupling of said second sensingelement comprises a second waveform.
 7. The capacitive sensor apparatusof claim 6, wherein: said varying capacitive coupling of said firstsensing element comprises a first phase; and said varying capacitivecoupling of said second sensing element comprises a second phasedifferent from said first phase.
 8. The capacitive sensor apparatus ofclaim 1, wherein said varying capacitive coupling of said first sensingelement and said varying capacitive coupling of said second sensingelement each comprises a sinusoidal waveform.
 9. The capacitive sensorapparatus of claim 1, wherein said capacitive coupling of said firstsensing element varies with variations in the dielectric constantbetween said contactable capacitive sensing reference surface andportions of said first sensing element.
 10. The capacitive sensorapparatus of claim 9, wherein said capacitive coupling of said secondsensing element varies with variations in the dielectric constantbetween said contactable capacitive sensing reference surface andportions of said second sensing element, said variations in thedielectric constant for said first sensing element different from saidvariations in the dielectric constant for said second sensing element.11. The capacitive sensor apparatus of claim 1, further comprising: athird sensing element having a length oriented along said first axis andconfigured to provide information corresponding to a spatial location ofsaid object relative to a second axis of said contactable capacitivesensing reference surface.
 12. A method for providing a capacitivesensor apparatus configured to sense a conductive object proximate acontactable capacitive sensing reference surface, said methodcomprising: providing a first sensing element having a length along afirst axis, said first sensing element having substantially constantdiameter along its length, said first sensing element configured to havevarying capacitive coupling, along said first axis, to said conductiveobject proximate to said contactable capacitive sensing referencesurface; and providing a second sensing element having a length alongsaid first axis, said second sensing element having substantiallyconstant diameter along its length, said second sensing elementconfigured to have varying capacitive coupling, along said first axis,to said conductive object proximate to said contactable capacitivesensing reference surface, wherein said first sensing element and saidsecond sensing element are conductive, and wherein each of said firstsensing element and second sensing element is configured to provideinformation corresponding to a spatial location of said conductiveobject relative to said first axis.
 13. The method as recited in claim12 wherein said providing said first sensing element comprises providinga substantially straight sensing element having a decreasing distancerelative to said contactable capacitive sensing surface along said firstaxis.
 14. The method as recited in claim 12, wherein said providing afirst sensing element having a length along a first axis comprisesproviding said first sensing element such that said varying capacitivecoupling of said first sensing element comprises a first waveform; andwherein said providing a second sensing element having a length alongsaid first axis comprises providing said second sensing element suchthat said varying capacitive coupling of said second sensing elementcomprises a second waveform.
 15. The method as recited in claim 12,wherein said providing a first sensing element having a length along afirst axis, said first sensing element having substantially constantdiameter along its length, said first sensing element configured to havevarying capacitive coupling, along said first axis, to said conductiveobject proximate to said contactable capacitive sensing referencesurface comprises: providing said first sensing element, wherein saidvarying capacitive coupling associated with said first sensing elementvaries with varying distance of portions of said first sensing elementto said contactable capacitive sensing reference surface.
 16. The methodas recited in claim 15, wherein said providing a first sensing elementhaving a length along a first axis comprises providing a first strip ofconductive material as said first sensing element; and wherein saidproviding a second sensing element having a length along said first axiscomprises providing a second strip of conductive material as said secondsensing element.
 17. The method as recited in claim 12, wherein saidproviding a first sensing element having a length along a first axiscomprises providing said first sensing element such that said varyingcapacitive coupling of said first sensing element comprises a waveformof a first phase; and wherein said providing a second sensing elementhaving a length along said first axis comprises providing said secondsensing element such that said varying capacitive coupling of saidsecond sensing element comprises a second waveform of a second phasedifferent from said first phase.
 18. The method as recited in claim 12,wherein said providing a first sensing element having a length along afirst axis comprises providing said first sensing element such that saidvarying capacitive coupling of said first sensing element comprises afirst sinusoidal waveform; and wherein said providing a second sensingelement having a length along said first axis comprises providing saidsecond sensing element such that said varying capacitive coupling ofsaid second sensing element comprises a second sinusoidal waveform. 19.The method as recited in claim 12, wherein said providing a firstsensing element having a length along a first axis comprises providingsaid first sensing element such that said capacitive coupling of saidfirst sensing element varies with variations in the dielectric constantbetween said contactable capacitive sensing reference surface andportions of said first sensing element.
 20. The method as recited inclaim 12, further comprising: providing a third sensing element having alength oriented along said first axis and configured to provideinformation corresponding to a spatial location of said object relativeto a second axis of said contactable capacitive sensing referencesurface.